This application proposes to examine the spatio-temporal organization of the neurophysiology of attention using multisite, multiple microelectrode recordings in a novel rat model of selective attention. The first set of experiments will determine the role that coherent, gamma band oscillations within and between primary sensory cortices play in attending to single or combinations of sensory events. The second set of experiments will determine the physiological mechanism(s) whereby an attention-enhancing drug improves behavioral performance. The hypothesis to be tested is that coherence in the neuronal firing in the gamma band frequency range across cortical sites is an underlying substrate of selective attention.